Rikako Ikee's quest for a perfect Asian Games slipped away Tuesday, when the women's 4x200-meter freestyle team swam to silver, a disappointing result after she had earlier kept her streak alive with her fourth gold in four events.

Ikee, who has already won the 100 freestyle, 50 butterfly, 4x100 freestyle gold, added the 100 butterfly title to her ever-growing collection at the GBK Aquatic Center with her fourth games record time, a 56.30-second swim.

In that race, Ikee, 18, beat China's Zhang Yufei and South Korea's An Seh Yeon to claim Japan's third gold of the night.

"I think I showed what I could do at a consistent speed since I was on pace for a finish in the 56-second range in the first half," Ikee said of her 100 butterfly gold.

"In the relay, I needed to take the lead, but over the first half of my leg I was holding back and my time was too slow."

The women's 4x200 team were on the back foot from the start as China pulled away to touch in a games-record 7:48.61, 5.22 ahead of the Japanese quartet.

(From left, An Seh Yeon, Rikako Ikee and Zhang Yufei)

Yui Ohashi earlier won gold for Japan in the women's 400-meter individual medley. The 22-year-old is competing in her first Asian Games but is the reigning world 200 IM silver medalist, and she was head and shoulders above Asia's best.

After falling behind fast-starting Kim Seo Yeong in the butterfly, Ohashi moved into the lead in the breaststroke leg and pulled away to win in 4:34.58.

"The big thing in the medley was coming from behind in the breaststroke," said Ohashi, who swam her team's slowest leg in the relay.

"You could say that in the relay I was worn out from my individual race, and I owe an apology for us finishing so far behind."

South Korea's Kim held on for silver and Japan's Sakiko Shimizu won bronze.

(Sun Yang)

Just minutes after Ohashi's triumph, Japan's Yasuhiro Koseki won an extremely tight men's 200 breaststroke, beating a fast-finishing Ippei Watanabe by a fingernail.

In winning his first Asian Games gold, Koseki hit the wall in 2:07.81 with Watanabe 0.01 behind. China's Qin Haiyang won the bronze medal.

"It was a very aggressive race as I expected," said Koseki. "At the end, it was really tough, but I am glad I could finish it up."

"I used up all that I had over the last 50 meters but I think that is something I can build on going forward."

China's three-time Olympic champion Sun Yang denied Japan gold in the men's 400 freestyle, dominating to finish more than four seconds ahead of a tight race for silver between Japan's Naito Ehara and Kosuke Hagino.

China opened the evening's competition in superb fashion when Liu Xiang set a women's 50 backstroke world record of 26.98. She led countrywoman Fu Yuanhui in a one-two finish with Japan's Natsumi Sakai in bronze almost a second behind the winner.

China also topped the men's 50 freestyle, Yu Hexin touching in 22.11 to beat Japan's Katsumi Nakamura by 0.09 with another Japanese swimmer, Shunichi Nakao, in bronze position.

(Liu Xiang)